Add the brown rice to a large pan of boiling water, cook, stirring occasionally, for about 25 minutes or until the rice is just tender; drain.
Meanwhile, heat half the oil in a wok or a large fry pan; stir-fry the beef, in batches, until browned all over; remove from the wok.
Heat the remaining oil in the wok, stir-fry the capsicum, broccoli and garlic until vegetables are just tender.
Add the combined cornflour, water, sauces, sesame oil and rice wine vinegar to the wok Bring to the boil then return the beef then the snow peas and spinach to the wok, stir-fry until heated through. Serve with the rice.